Man-made climate change is here.

Climate change is a reality we can no longer ignore. We see the impacts in our everyday lives, from extreme superstorms, to heat waves, to massive wildfires and droughts. But climate denial, bankrolled by Dirty Energy companies and justified by pseudoscience, persists.

Reality Drop, inspired by Skeptical Science, is a library of science-based rebuttals to climate change deniers.

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Showing 110 myths:

Deniers say:
The greenhouse effect is just a theory; it hasn’t been proven by real-world data.

Science says:
Two centuries of scientific research tell us the greenhouse effect is real.

Without the greenhouse effect generated by our atmosphere, heat from the sun would be quickly lost to space and the Earth would be an icy ball. Nearly 200 years of scientific research — including direct observations of the greenhouse effect in action — back up this reality. But although we do need the greenhouse effect, we certainly don’t need to make it stronger by pumping carbon pollution into the air. The more carbon we put into the atmosphere, the more heat we trap and the hotter it gets. And around the world, we’re already starting to see the negative effects of a greenhouse effect on steroids.

Deniers say:
The idea that the greenhouse effect can warm the planet contradicts the laws of physics.

Science says:
Physics disproves climate change? Try again.

The greenhouse effect is perfectly consistent with the laws of physics, and that includes the second law of thermodynamics. Simply put, this law tells us if we put a hot thing next to a cold thing, heat will flow out of the hot thing and into the cold thing. Deniers look at this rule and ask, “If the atmosphere is cooler than the surface of the Earth, how can it be responsible for warming the Earth?” It’s a nice try, until you consider the fact that it’s the hot sun that warms the planet initially. Sunlight comes in and the Earth radiates heat outwards, to cooler outer space — just as the laws of physics suggest. Greenhouse gases trap some of the heat and redirect it back toward the planet’s surface.

Scientists know our climate is changing, primarily due to carbon pollution from the burning of dirty energy like oil and coal. It's true that other factors affect our climate, including other greenhouse gases such as methane. Solar variation, volcanoes and clouds all affect the climate, too. But scientists take all these factors into account and weigh the contributions that each one makes to our climate. When they do, it's clear that man-made carbon dioxide pollution is overwhelmingly responsible for the warming we’re experiencing now.

Science says:
Carbon dioxide is a control knob on our climate. The more we pollute, the warmer it gets.

Our climate has warmed over the last 130 years because of carbon pollution from human activities. At other times in the Earth's history, long before humans started burning fossil fuels, the climate warmed for other reasons, such as changes in the Earth's orbit. As the temperature increased in the past, oceans also released more carbon dioxide because warm water holds less carbon dioxide than cold water. This led to more warming, and even more carbon dioxide as a result. The bottom line is this: The fact that global warming happened for different reasons hundreds of thousands of years ago does not change the fact that today, human activity is responsible for climate change. We are putting 35 billion tons of carbon pollution into the atmosphere every year. And scientists agree that is the reason our planet is now warming.

Deniers say:
What about 400 million years ago, when CO2 was five times higher than it is right now?

Science says:
Looking back at naturally-caused global warming hundreds of millions of years ago is a nice history lesson, but it tells us little about man-made global warming today.

Because of pollution from dirty energy like coal, there is more carbon dioxide in the atmosphere now than in nearly a million years. More than 400 million years ago, however, carbon dioxide concentrations were much higher than today, and the world was mostly a lot warmer as well. Back then, the warming was indeed due to natural causes.

What does that tell us about climate change today? Not much. The world was a completely different place 400 million years ago. The continents were in different positions. Life was almost entirely restricted to the oceans. Trees didn’t exist. Humans didn't exist. In other words, not all pre-historic climate facts are relevant to the modern climate crisis.

Deniers say:
You can’t rely on the global CO2 data. Ice cores are inaccurate, and modern instruments are often placed near volcanoes.

Science says:
From Hawaii to Antarctica, data collected from all over the world tell us one thing: Carbon pollution is going up.

Scientists don’t just measure carbon dioxide in one way, or in one place. Gas bubbles trapped in ice cores show us what carbon dioxide concentrations were like deep in the Earth’s past. Measurements made at the Mauna Loa Observatory in Hawaii show us that carbon dioxide has been increasing in our atmosphere. And Mauna Loa isn't the only place this pattern is seen; data from observatories in Alaska, American Samoa and Antarctica all show the same upward trend. All the measurements we have from an extensive array of sources tell us this: Carbon dioxide levels are rising.

Deniers say:
One of the most important records of the Earth’s CO2 concentrations is 30 miles away from a carbon dioxide-spewing volcano.

Science says:
Scientists adjust for the fact that Mauna Loa is a volcano to make sure their measurements are accurate.

Continuous measurements taken at the Mauna Loa Observatory clearly show that carbon dioxide has been increasing in the atmosphere since 1958. And Mauna Loa isn’t the only place this pattern is seen; data from observatories in Alaska, American Samoa and Antarctica all show the same upward trend. Scientists were well aware when they selected Mauna Loa that it’s a volcano. But they also knew that most of the time, the wind blows volcanic gases (including carbon dioxide) away from the observatory. When the wind infrequently shifts, there’s an obvious spike in carbon dioxide. Measurements from the “volcano days” are removed from the Mauna Loa dataset. That's how scientists make sure the data are accurate.

Deniers say:
Volcanoes are able to emit more carbon dioxide in a single day than humans could emit over centuries.

Science says:
Here's something to blow your top off: Humans send up 135 times more carbon dioxide than volcanoes.

Think volcanoes emit more carbon dioxide than humans? You’ve got it backwards. Humans release at least 135 times more carbon dioxide to the air than volcanoes. Emissions from Mount Pinatubo, the strongest volcanic eruption over the past 50 years, amounted to just 0.2 percent of human emissions in 1991. Just 0.2 percent! By releasing 35 billion tons of carbon dioxide into the atmosphere each year, humans are the main drivers of climate change.

Deniers say:
CO2 in the air comes from volcanoes, the oceans and other natural sources, not humans.

Science says:
What's causing climate change? Human beings. Just ask 97% of the top climate scientists in the world.

How can scientists be sure that humans are increasing heat-trapping carbon dioxide? First, the carbon dioxide in the atmosphere has increased about 40 percent since humans started burning dirty energy like coal and oil on a wide scale. Second, the carbon from dirty energy has a unique chemical signature that allows scientists to tell it apart from other sources of carbon. Third, the amount of oxygen in the atmosphere is decreasing. It takes oxygen to burn trees or coal, and the more burning we do, the more oxygen we suck up. The evidence is inescapable: Humans ARE changing our climate.

Deniers say:
If you’re serious about wanting to reduce carbon pollution, you should stop breathing.

Science says:
Take a deep breath. Don't worry, that has nothing to do with climate change.

A human exhales about 1 kilogram of carbon dioxide a day. That sounds like a lot when you consider there are about 7 billion of us on the planet. But the carbon we breathe out doesn’t magically appear — it comes from the carbon-based things we eat. And as you may recall, plants need carbon dioxide to make their own food via photosynthesis. So, we have a closed cycle: the carbon taken in by plants becomes food for us (either directly or indirectly), and then we breathe the carbon out ... and then plants take it in again. When we burn dirty energy, we’re adding carbon to the air that had been out of the loop for millions of years and was stored underground as deposits of coal, oil, and gas. Once we take that carbon out of the ground, it will be in our atmosphere for thousands of years to come.

Deniers say:
Carbon dioxide helps plants grow — it is not something that we should regulate as a toxic pollutant.

Science says:
We don't need the Supreme Court to tell us carbon dioxide is a pollutant -- we just have to look at our changing world.

Carbon dioxide, which we send into the atmosphere when we burn fossil fuels, is a pollutant because it’s driving dangerous climate change. This is a scientific reality that has been recognized by leading scientists, and a legal reality recognized by the U.S. Supreme Court. It’s true that carbon dioxide exists naturally: We breathe it out, plants need it to survive, and it makes up an important part of our atmosphere. Without carbon dioxide and other greenhouse gases, the Earth would be an icy ball. But “natural and important” doesn’t mean “more is better." Think of trace nutrients in our foods like copper and magnesium: We need them in tiny amounts to survive, but in excess, copper and magnesium can make us very sick. Since the start of the Industrial Revolution, we’ve increased the level of carbon dioxide in the atmosphere by 40%. This excess carbon dioxide is warming up our planet and is having negative impacts on plants, animals, our economy and our health.

Deniers say:
How could such a small amount of carbon dioxide have any meaningful effect on the climate?

Science says:
Like alcohol or ibuprofen, even very small amounts of carbon dioxide can have huge effects.

Yes, carbon dioxide makes up just 392 parts per million, or about 0.04% of our atmosphere. Guess what: That doesn’t mean its impact isn’t serious. That would be like saying drivers aren’t drunk if they only have a trace of blood alcohol: 0.08%. Or that ibuprofen won’t help your headache because it’s only 0.0003% of your body weight. The point is, small amounts of very active substances can have large effects. Carbon dioxide is a trace gas, but it has increased by 40% since the Industrial Revolution and is warming our planet at an incredibly fast rate. And that’s the part that matters.

Deniers say:
There's a lot of carbon in the atmosphere and only a tiny part of it is manmade.

Science says:
Not all the carbon in the air comes from humans. Problem is, humans send up an extra dose of carbon that nature can't handle.

Carbon cycles naturally through the environment. It is taken up by plants and breathed out by animals, and it moves back and forth between the air and the oceans. Prior to the Industrial Revolution, this natural cycle was more or less balanced. The carbon that entered the atmosphere was roughly equal to the amount that was absorbed and stored. But by burning dirty energy like oil and coal, we’re injecting “new” carbon into the cycle ⎯ carbon that used to be locked underground. The ocean and plants on land are working extra hard to absorb some of this excess, but they can’t take it all. That’s why carbon pollution is accumulating ⎯ and we have more carbon dioxide in the atmosphere than any time in nearly a million years.

Deniers say:
So what if we're emitting a little more CO2? That doesn't mean we're responsible for climate change.

Science says:
Carbon dioxide traps heat. The more carbon we send into the sky, the hotter it gets.

More than a century ago, scientists figured out that carbon dioxide and other greenhouse gases trap heat. Many lines of evidence now confirm our planet is warming because of carbon pollution released when humans burn fossil fuels like oil and coal. One of the most important lines of evidence is a closer look at the wavelength, or “type,” of heat being trapped in the Earth’s atmosphere. Carbon dioxide traps specific wavelengths of heat energy, and satellite and surface measurements show that in recent decades, less heat at those specific wavelengths is escaping to space. Given that carbon dioxide concentrations in the atmosphere have increased a whopping 40% since the start of the Industrial Revolution, it’s really no wonder our planet’s temperature is rising.

Deniers say:
Human emissions of CO2 don’t vary much from year to year, but the concentration of CO2 in the atmosphere varies a lot. It clearly doesn’t come from us.

Science says:
We're putting more carbon into the atmosphere than nature can handle. That causes global warming.

The concentration of carbon dioxide in the atmosphere correlates closely — but not perfectly — with the amount of carbon pollution emitted by human activities. That’s because plants, soils and the ocean take some of the carbon back out of the atmosphere. This is a good thing, because otherwise the planet would be heating up even faster than it is now. Unfortunately, we’re putting more carbon pollution into the atmosphere than natural systems can absorb, and that's why the planet is warming.

Deniers say:
The more carbon we release into the atmosphere, the less it matters.

Science says:
The atmosphere isn't a sponge; it can't get "saturated" with carbon dioxide. The more carbon we put into the atmosphere, the hotter it gets.

Deniers have argued that our atmosphere is "saturated" with carbon dioxide. In other words, they’re saying that adding more carbon dioxide to the atmosphere doesn’t strengthen the existing greenhouse effect. But carbon dioxide traps specific wavelengths of heat energy. And satellite and surface measurements show that in recent decades, less heat at those specific wavelengths is escaping to space. This is evidence that carbon dioxide is strengthening the greenhouse effect.

Deniers say:
We’ve been emitting more carbon dioxide since the start of the Industrial Revolution, but temperatures go up and down from year to year.

Science says:
We have warm years and cold years, but over the long run, global temperatures have gone up.

Carbon dioxide traps heat. We've known that since the 19th century. And as carbon pollution from dirty energy has gone up, the Earth's temperature has increased as well. Since 1880, the world has warmed nearly 1.5 degrees Fahrenheit (0.8 degrees Celsius) — and more than half the warming has occurred since 1979. But natural variations mean that the increase isn't steady from year to year. One year might be unusually cold, the next might be unusually warm. That’s why the lines on a temperature graph zigzag from year to year. When scientists filter out the “noise” from short-term variation, clear trends emerge. The global average temperature over the last hundred years has risen steadily along with carbon pollution.

A 2010 study found that methane, ground-level ozone, and black carbon (i.e., soot) increase the global warming effect of carbon dioxide by 65 percent. Some people misread this as a suggestion that carbon dioxide was only responsible for 35 percent as much global warming as previously believed. What it actually says is that these short-term pollutants cause warming IN ADDITION to carbon dioxide. Nothing in the study changes the fact that carbon dioxide is the main cause of the warming we’re seeing today.

97 percent of top climate scientists and every major National Academy of Science agree that man-made pollution is warming our climate. Here’s how they know. First, the concentration of carbon dioxide in the atmosphere has increased about 40 percent since humans started burning dirty energy like coal. Second, the carbon from dirty energy has a unique chemical signature that differentiates it from other sources of carbon — so we can confirm that it's coming from us. Third, we know it is carbon — not natural forces like the sun — that's responsible for the recent increase in global temperatures. Why? The lower level of the atmosphere is warming, while the middle layer is cooling. If the sun were responsible for most of the recent temperature change on Earth, both layers of the atmosphere would be warming. The evidence is inescapable: Humans ARE changing our climate.

Deniers say:
How could we have an impact on an old and enormous planet that's been regulated by natural processes for billions of years? It’s impossible.

Science says:
Thanks to humans, the carbon in the atmosphere has gone up by 40%. It's no surprise that would have a big impact on our climate.

It's true that for most of history, human beings sent insignificant amounts of carbon pollution into the atmosphere — not enough to affect our climate. Since the Industrial Revolution, however, we have been burning fossil fuels like coal and oil on an unprecedented scale. We have increased the concentration of carbon dioxide in our atmosphere by about 40 percent — and this enormous increase in carbon dioxide has warmed our planet.

Deniers say:
Temperature measurement usually takes place in cities, which retain more heat than rural areas.

Science says:
Even when you account for the urban heat island effect, it's clear that the Earth is getting warmer.

Temperature records from around the world — from weather stations in both urban and rural areas, and from weather balloons and satellites — tell us the world is warming. The “urban heat island effect” is a real phenomenon. Cities, with their abundance of black roofs and asphalt parking lots, tend to absorb more sunlight and radiate more heat than the surrounding countryside. But scientists take this effect into account when they process temperature data. When the readings from all rural and urban stations are taken together and adjusted for the urban heat island effect, it’s clear global average temperatures are increasing.

Deniers say:
The sun's energy has increased over the last several hundred years, and that's why Earth is getting warmer.

Science says:
The sun is responsible for a lot -- like sustaining life. But humans are responsible for the global warming we see today.

The sun is our primary source of energy here on Earth, and yes, it most definitely keeps us warm. But here’s the thing — without greenhouse gases like carbon dioxide in our atmosphere, the Earth would be a lot colder because most of the sun’s heat would quickly disappear into space. Today, we’re putting more and more heat-trapping carbon pollution in the atmosphere by burning dirty fossil fuels like oil and coal. The sun’s output increased slightly in the first half of the 20th century, but satellite measurements show that output has barely changed in recent decades. The variation in the sun’s energy over the course of the 20th century just isn’t significant enough to account for the rapid global warming we’re experiencing now.

Deniers say:
It's not just the Earth that's warming — what about Mars?

Science says:
We don't know if other planets are warming. We know the Earth is — and it's our own fault.

It’s true that the sun affects the climates of the planets in our solar system — including our planet. If the sun’s energy significantly increased, we would expect most or all of the planets to warm up. But there’s no good evidence of consistent warming on planets other than Earth. And the variation that’s occurred in the sun’s energy over the course of the 20th century just isn’t significant enough to account for the large-scale climate change we’re seeing here. Multiple lines of evidence confirm that humans, not the sun, are the primary cause of the climate change that's happening here on Earth.

Science says:
Let's get serious. Global warming has nothing to do with cosmic rays — or anything else from outer space.

Some scientists believe cosmic rays (high-speed particles from outer space) are one of the reasons clouds form in the Earth's lower atmosphere. Hypothetically, if fewer cosmic rays were bombarding Earth, fewer clouds would form and the planet would warm. But here’s the thing: The number of cosmic rays hasn’t changed much in recent decades, and scientists have failed to find a consistent relationship between cosmic rays and clouds. There is overwhelming evidence that the Earth has been steadily warming since the Industrial Revolution, and the reason for this warming is pollution from dirty energy like coal and gas.

Deniers say:
The El Niño Southern Oscillation (ENSO) and other similar natural cycles are the dominant causes of global warming.

Science says:
El Niño and La Niña make temperatures change from year to year. In the long run, the Earth is steadily warming.

The climate is warming — and that means if you look at a graph of average global temperatures, you’ll see an overall upward trend over the last 130 years. But from year to year, you’ll also see the temperature wiggle up and down. Part of that wiggle comes from natural climate patterns such as El Niño and La Niña. The world tends to be slightly warmer during El Niño episodes — 1998 is a great example of that. During La Niña episodes, the world tends to be slightly cooler. Here’s the thing: Despite variations from year to year, the Earth is still warming up.

Deniers say:
There’s a temperature pattern in the Pacific Ocean that causes warming and cooling every 20-30 years.

Science says:
The Pacific Decadal Oscillation shifts heat around the globe, but the Earth is steadily warming overall.

The climate is warming — and that means if you look at a graph of average global temperatures, you’ll see an overall upward trend over the last 130 years. But from year to year, you’ll also see the temperature wiggle up and down. Part of that wiggle comes from natural climate patterns such as the Pacific Decadal Oscillation (PDO). The PDO cycles between warm and cool phases that typically last 20-30 years each. Here’s the thing: Internal climate cycles like the PDO primarily redistribute heat around the planet. Unlike carbon pollution, they don’t INCREASE the total amount of heat held by the oceans and the atmosphere. When you look at the long-term trend over decades, the overwhelming evidence shows that temperatures are rising and humans are to blame.

Deniers say:
Water vapor is a greenhouse gas, and there’s a lot more of it in the atmosphere. So why all the focus on CO2?

Science says:
Carbon dioxide is like a control knob on our planet's thermostat. More carbon pollution = more global warming.

Here's what's most important: If you increase the amount of carbon pollution, the planet warms. And humans have increased the amount of carbon dioxide by about 40% by burning dirty energy. Water vapor is important, too, but the details are a little technical. As carbon dioxide traps heat and the planet warms, two important things happen: 1) More water evaporates from the oceans and land, and 2) the atmosphere retains more water (because warm air can hold more moisture than cold air). Then, since water vapor is a greenhouse gas, it causes the temperature to go up even further. Studies show that the water vapor "feedback loop" roughly doubles the warming caused by carbon dioxide.

Deniers say:
Methane is a much more powerful greenhouse gas than carbon dioxide.

Science says:
Does methane trap heat? Yes. But carbon dioxide has caused three times more warming than methane.

Even though methane is better at trapping heat than carbon dioxide, there’s a lot less of it in the atmosphere. Over the last century, carbon dioxide has caused about three times more warming than methane. And sorry, we can’t duck responsibility for methane-induced warming any more than we can for carbon dioxide-induced warming. At least half of the methane in the atmosphere comes from sources like livestock (we’re not talking wild cows, here) along with coal mines and landfills.

Science says:
The ozone hole has an insignificant impact on our climate. Carbon pollution is the main cause of global warming.

We all know there’s a “hole” in the ozone layer — a section of the atmosphere over Antarctica where the concentration of ozone is a lot lower than it should be. But the logic that sunlight is streaming in through this hole and causing climate change just doesn’t work. Like carbon dioxide, ozone is a greenhouse gas that traps heat. So the depletion of the ozone layer actually has cooled Earth’s climate very slightly. Why are we still seeing warming then? Because we’re putting 35 billion tons of global warming pollution into the atmosphere every year.

Science says:
Soot pollution changes the climate in the short term. Carbon pollution is the main culprit over the long term.

The main cause of the climate change we’re seeing now is greenhouse gas pollution, which we put into the air when we burn dirty energy like oil and coal. Soot, also called "black carbon," is a contributor, too, but not to the same extent. That’s because soot only stays in the air for days to weeks. Carbon dioxide, on the other hand, has a lifetime of a century or more. Reducing soot would do a lot in the short term to help slow warming. But to protect our climate in the long term, we need to reduce greenhouse gas pollution from dirty energy.

Deniers say:
Aerosol particles reflect sunlight. There are fewer aerosols in the atmosphere now, so that's why the planet is warming.

Science says:
Aerosol pollution impacts our climate over the short term. Carbon pollution is the main culprit over the long term.

The main cause of the climate change we’re seeing now is carbon pollution, which we put into the air when we burn dirty energy like oil and coal. But carbon dioxide and other greenhouse gases aren’t the only air pollution released by human activities. For example, the harmful haze you see and breathe in big cities like Los Angeles or Philadelphia is made of “aerosols," a name for various kinds of tiny particles in the atmosphere. Carbon pollution traps heat and causes warming, but aerosol pollution in haze reflects sunlight. This temporarily masks some of the warming we would otherwise see due to carbon pollution. Thankfully, the U.S. and many other countries around the world have worked to reduce haze-forming aerosol pollution, and we can all breathe a little easier. But this also means the slight cooling effect of aerosols is reduced, and the world is a little warmer as a result. Here's what's important: It's carbon pollution, not aerosols, that is steadily warming our planet.

Deniers say:
Volcanic eruptions have decreased for the last couple hundred years, so that’s why we’re seeing warming.

Science says:
Climate change doesn't come from volcanoes. It's us.

In the early part of the 20th century, a slowdown in volcanic activity helped warm the planet slightly. Large volcanic eruptions eject sulfur dioxide, which rapidly forms tiny particles in the air known as "aerosols" that block sunlight. So with less volcanic activity, you’d expect to see more warming. But this happened at the same time that humans were just starting to burn dirty fossil fuels in earnest. And the more fossil fuels we burned, the more carbon pollution we put in the atmosphere. Today, we’re putting about 35 billion tons of heat-trapping carbon pollution into the atmosphere every year — and that’s what’s causing most of the global warming we’re seeing today.

The engines, appliances and electronic devices we use release heat during operation. For instance, think about a laptop computer, which can get uncomfortably warm if you rest it on your legs for too long. That heat is often called “waste heat” because it escapes without being put to good use. So, given how many machines and devices we use — particularly in rich, industrialized countries — could waste heat be warming the planet? Not really. Waste heat is currently responsible for about 100 times less global warming than carbon dioxide and other greenhouse gases. In other words, it’s not a big problem. Not like the 35 billion tons of carbon pollution we put into the air every year when we burn dirty energy like oil and coal.

Deniers say:
The climate has changed over and over, long before humans had anything to do with it.

Science says:
Climate change doesn't just happen — it happens for a reason. And today, the reason is us.

Has our climate changed before? Absolutely! Nobody disagrees with that. But arguing that humans aren’t the cause of climate change today is like arguing humans can’t cause forest fires because they've been started by natural causes in the past. Basic physics tells us something important: Climate change happens for a reason. Some past changes in the climate were driven by the sun burning brighter, or by an increase in volcanic activity. That’s not the case now. There is overwhelming scientific evidence that humans are causing most of today’s climate change by burning dirty fossil fuels and sending carbon pollution into the atmosphere at an unprecedented rate.

Deniers say:
Climate goes through natural cycles. The warming we’re seeing now is just part of a 1,500-year cycle.

Science says:
Some natural cycles make it warmer in one part of the world and colder in another. Man-made climate change makes it warmer everywhere.

From ice core data we can see that on approximately 1,500-year cycles, the northern polar region has warmed while the southern polar region has cooled. This "see-saw" effect redistributes the planet’s heat, but total heat in the global system stays the same. In other words, regional temperatures change, but the average global temperature doesn’t. These regional cycles are unlike what we’re observing now. The global temperature is rising because of carbon pollution from human activities. And there’s nothing natural about that.

Deniers say:
The last 150 years of warming is just a natural recovery from the last ice age.

Science says:
A planet doesn't "recover" from an ice age like we do from hypothermia. The Earth is warming up, and carbon pollution is to blame.

The “Little Ice Age,” the most recent cool period in the Earth’s history, may have been triggered by decades of intense volcanic activity. Scientists generally agree that the Little Ice Age ended in the late 19th century. So, could the warming we’re seeing now simply be a “recovery” after the Little Ice Age? No. Although the climate goes through cycles, there isn’t a normal recovery point. In other words, warming after an ice age isn’t like a human naturally recovering from hypothermia. Something has to force the climate to get warmer. In the early part of the 20th century, the Earth warmed because of less volcanic activity and more solar activity. But most of the warming from the mid-20th century onward has been due to carbon pollution from dirty fuels. And now, the planet is warmer than at any point in the last 1,000 years … meaning it’s warmer than well before the start of the Little Ice Age.

Deniers say:
If you think it’s warm now, look back at the Medieval Warm Period.

Science says:
The so-called Medieval Warm Period was actually cooler than it is today under man-made climate change.

When climate deniers want to change the subject away from the warm temperatures we're experiencing now, they sometimes claim it was warmer in Medieval times. First off, during the so-called "Medieval Warm Period," some regions experienced unusually warm temperatures, while others were really cold. If you average everything out, global temperatures during this period were actually COOLER than they are now. Moreover, in Medieval times, warming or cooling happened for natural reasons, and there was no significant carbon pollution to warm our atmosphere. Overwhelming evidence points to carbon pollution from dirty energy like coal and gas as the main cause of today’s climate change.

Science says:
The hockey stick graph has been confirmed again and again. There's also plenty of other evidence to show us the Earth is warming.

The famous “hockey stick” study and graph told us that the 20th century has been the warmest of at least the past 1,000 years. This conclusion was based on tree rings, ice cores, coral and other records as proxies for temperature. Since the hockey stick was published in 1999, several independent studies have found the same thing. The hockey stick study has been analyzed and upheld. In addition to this graph, there are multiple confirming lines of evidence that tell us man-made climate change is a reality.

Deniers say:
The air was much dirtier during the Industrial Revolution. Why wasn’t there any global warming back then?

Science says:
Half the carbon pollution from humans took place after 1979. It's no surprise the world is warming up a lot faster since then.

Since 1880, 30 years after the Industrial Revolution ended, the world has warmed nearly 1.5 degrees Fahrenheit (or 0.8 degrees Celsius). But look a little closer at the data, and you’ll see something interesting. More than half the warming has occurred since 1979. That’s not a surprise, given that more than half of the carbon pollution from human activities has also happened since the 1970s. We’re putting about 2,700 times more carbon dioxide into the atmosphere now than we were at the beginning of the Industrial Revolution. That's why the planet is warming up so much faster now than it did from 1880 to 1979.

Deniers say:
How can we be getting warmer when the hottest year on record in America was eight decades ago?

Science says:
2012 was by far the hottest year on record in America’s Lower 48.

In the contiguous United States, the record wasn’t even close. 2012 was the warmest year on record, and 1 degree Fahrenheit warmer than the previous record in 1998. 1934 comes in fourth.

But here's what matters the most: One year only gives us a snapshot in time, not a long-term trend. There’s also no reason to expect the temperature trends in the U.S. — which only makes up 2% of the planet’s surface — to perfectly track the average temperature of the planet. Globally, 2010 was tied with 2005 for the hottest year on record, and 1934 didn’t even make the top 60. Nine of the ten hottest years on record have occurred since the year 2000.

Deniers say:
From 1945 to 1975, the planet cooled. What happened to global warming?

Science says:
In the middle of the 20th century, the global climate cooled over the short term. Carbon dioxide pollution is warming our planet over the long term.

Over the last 130 years, global temperatures have increased due to carbon pollution from the burning of dirty energy like oil and coal. It’s true though that around the middle of the last century, the temperature record shows a short-term cooling trend. Generally, the trend has been attributed to an increase in sulfur pollution, which rapidly forms tiny particles in the air known as "aerosols" that reflect incoming solar energy back into space. The surge in sulfur dioxide pollution was mostly due to industrial activities that picked up after World War II, as well as several volcanic eruptions in the early 1960s. We’ve come a long way since then to limit sulfur pollution, since it’s bad for our health and causes acid rain. Even today though, we still emit some. And even today, sulfur pollution is masking some of the warming caused by carbon pollution from dirty energy. None of this changes the fact that the Earth is steadily warming and carbon pollution is the primary cause.

Deniers say:
Climate change isn't happening at all. If you think the world is getting warmer, then I'd love to see you prove it.

Science says:
Scientists have known about global warming for decades. It's real. So let's move on to what we can do about it.

There is overwhelming evidence that our climate is warming due to pollution from human activities. That's the conclusion reached by 97 percent of top climate scientists and every major National Academy of Science in the world. When we burn dirty fossil fuels like oil and coal, and when we cut down forests that store carbon, we pollute our atmosphere and warm our planet. This is not controversial: It's a reality we've understood for decades.
And we’re starting to feel the effects now. Nine of the ten hottest years on record have occurred since the year 2000. Extreme weather events like heat waves, heavy rains and drought are becoming more common and more severe. Coastal communities all over the world are preparing for the impacts of sea level rise. The debate over the basic science of climate change is over. So let's move on to a much more productive discussion on what we can do about it.

Deniers say:
The weather stations that monitor temperature in the U.S. are placed in unreliable locations.

Science says:
There is plenty of evidence to show us the Earth is warming, including carefully tested weather stations.

Unfortunately, not every temperature monitoring station in the U.S. is located in the best place. Some stations are located too close to paved surfaces, buildings or other artificial sources of heat. So it’s reasonable to ask: Can U.S. thermometers that show “warming” be trusted? Yes, it turns out. Sites in ideal and less-than ideal locations report nearly identical trends. The lesson here? You can’t tell how good a thermometer is just by looking at it. You have to actually examine the data it collects in the context of a larger network of stations. And monitoring stations and temperature records aside, there are many other ways we can tell the planet is warming. Glaciers are melting, Arctic sea ice is declining, and the oceans are warming up. Multiple lines of evidence show us that climate change is happening and humans are the cause.

Data from several independent satellites show the troposphere (the part of the atmosphere in which we live) is warming. This trend is one of many lines of evidence that the Earth is warming because humans are putting carbon pollution into the atmosphere. The argument should really end here, but let’s talk for a second about why, back in the 90s, it appeared as though the tropospheric warming trend wasn’t very pronounced. It turns out the methodologies scientists used decades ago to compile and interpret the data weren’t perfect. As techniques improved, it became clear that the troposphere was warming — a fact that is consistent with basic physics.

Deniers say:
So 1998 was a warm year, but since then, global warming has stopped.

Science says:
2005 was hotter than 1998, and the ten hottest years on record have occurred in the last 15 years.

As our climate changes, some years will be warmer than others. Yes, 1998 was unusually warm (partly it because was a strong El Niño year). But overall, 2005 and 2010 ⎯ which were tied for the warmest years on record, globally ⎯ were both hotter, and the 10 hottest years on record have all happened since 1998. Scientists have observed rising temperatures, rising sea levels, melting glaciers, melting Arctic sea ice, and increased humidity over the last several decades. The full range of available data since 1880 conclusively shows the world is warming. And we can expect that trend to continue as long as humans send carbon pollution into the atmosphere.

Deniers say:
The temperature trend is going down, especially over the last 15 years.

Science says:
Temperatures go up and down from year to year, but the Earth is warming over the long run.

Temperature records from around the world clearly show that the Earth has been warming since 1880. Those who argue it's cooling are either confusing cold weather with climate, or are referencing data that measure only short-term changes in global surface temperatures. Natural climate patterns like El Niño or La Niña can make the average global temperature fluctuate from year to year; that's why the lines on a global temperature graph zigzag. It also helps explain why short periods of cooling can occur within longer-term periods of warming. When scientists look at the big picture, though, a clear trend emerges: The world is warming. Temperature records from thermometers aside though, this reality is confirmed by the fact that ice sheets are shrinking, Arctic sea ice is declining, and the oceans are getting warmer.

Deniers say:
Did you hear about the record cold snap? Where's the global warming now?

Science says:
Even with climate change, it still gets cold sometimes. But hot days are happening more often.

Since 1950, hot days have become more common and cold days have become less common around the world. In the U.S., record-high temperatures are being set more than twice as often as record-cold temperatures. But the bottom line is this: “Less cold” doesn’t mean “never cold.” Cold days will happen less often as the world warms, but they won’t go away.

Deniers say:
The idea that we’re warming the globe is debunked every time we have to bundle up and head outside to shovel away some climate change.

Science says:
Global warming means there's less snow overall. But it could also bring more extreme snowstorms.

Any time there’s a big snowstorm, someone scoffs, “Global warming?! Yeah, right!” There are a few problems with that. First: It confuses a short-term, local event with the long-term trend that the planet is getting warmer. But here’s another fact that might surprise you. Even though the total amount of snow has declined in parts of the world over recent decades, there have been an increasing number of very heavy storms. That’s because a warmer climate increases evaporation, drawing moisture both from the oceans and the land. When that increased atmospheric moisture feeds into a storm, it can make the storm really, really big. The result: less snow overall as temperatures increase, but more extreme snowstorms.

Deniers say:
How can we be warming? Spring gets here the same time every year.

Science says:
It's not your imagination: Spring is coming sooner than it used to.

There is mounting evidence that as temperatures rise, winters are getting shorter and spring is coming sooner. For example, the peak spring runoff is happening more than 20 days earlier in rivers and streams across the American West. In the U.K., the average first flowering date of more than 400 plant species occurred earlier in the last 25 years than in any other period since 1760. Migratory birds are arriving earlier in their summer breeding grounds in Australia, Europe, Asia, and North America. This is known as “season creep.”

Deniers say:
Ice ages come every 11,500 years. The last ice age was 11,500 years ago. Do the math.

Science says:
Global warming is happening now. An ice age may or may not happen in thousands of years.

The world is warming because of carbon pollution from fossil fuels like oil and coal. Without those human activities, the world would actually be COOLING slightly. Does that mean we’d be heading into an ice age? Maybe … in the next couple thousand years or so. Ice ages are triggered by natural forces like volcanoes and changes in the Earth’s orbit and tilt. But because the concentration of carbon dioxide is so much higher now than any time in nearly 1 million years, ice sheets are shrinking instead of growing. We need to focus on solving the climate crisis unfolding today, rather than worrying about an ice age thousands of years from now.

One thing is certain about the Earth’s climate: It’s warming — and warming fast — because of carbon pollution from human activities. What’s less certain is how much the planet will warm by the end of the century. For one thing, it’s hard to say just how much carbon pollution humans will pump into the atmosphere 50 or 100 years from now. The other thing that’s a little unclear is “climate sensitivity," or how much the Earth will warm in response to carbon pollution in our atmosphere. The best estimates suggest doubling the amount of carbon dioxide in the atmosphere would increase the world’s temperature by 3.6-8.1 degrees Fahrenheit (that's 2-4.5 degrees Celsius). Even a 2-degree Celsius rise is expected to disrupt our lives and challenge our ability to adapt. We had better hope that the climate sensitivity is low — but we shouldn’t bank on it.

The vast majority of climate scientists are certain the world will continue to warm as we add carbon pollution to the atmosphere. What’s less certain is the exact AMOUNT of warming. Why? It all comes down to feedbacks — processes that amplify or reduce man made warming. Some feedbacks are well understood. Take Arctic sea ice, for example. As the climate warms and sea ice melts, less sunlight is reflected back to space, and more warming happens. But the net effect of cloud feedbacks is less well known. Some kinds of clouds warm the climate; others cool the climate. What will the overall result be? There’s growing evidence that at worst, the clouds will have a net warming effect. At best, they’ll have a slight cooling effect. But there’s no reliable evidence that clouds will somehow cool the climate enough to counteract man made warming.

Deniers say:
The IPCC uses flimsy evidence to try to scare us about global warming.

Science says:
If anything, the IPCC has underestimated the impacts of climate change.

Deniers love to hate the United Nations Intergovernmental Panel on Climate Change (or the “IPCC”), an international scientific body that reviews and assesses the best available climate research produced worldwide. Hundreds of independent scientists review the peer-reviewed research on climate change and summarize it in a few reports. Then hundreds more experts review their work. And then, the world’s governments go through the reports line by line. What does this mean? It means the end product is a consensus document —or in other words, it generally underestimates what will happen to the Earth’s climate.

Further, fossil fuel emissions are currently close to the "worst-case" IPCC projections. Arctic sea ice is declining much faster than the IPCC predicted. Indeed, in many cases, IPCC projections have underestimated the speed and intensity of observed climate change.

Deniers say:
Climate models have nothing to do with reality — so how can we use them to predict the future?

Science says:
The models do a good job of simulating past climate change, and they are a reliable guide to the future.

We know our climate is warming — and models show it will continue to warm into the future. But how can we trust something that is “just a model”? Climate models are kind of like cars. The rules of physics form the foundation of climate models, just like wheels are part of a car body. And real-life data make models run, much like gas in a car’s tank. Like cars, climate models are thoroughly tested before they’re considered reliable. One way to test a model is to ask what happened in past decades. If the model represents what actually occurred, we can expect the model will be reasonably reliable in projecting future change. Thanks to this diligence, our climate models have a great track record. Moreover, they’ve tended to be conservative in their projections, meaning that temperatures and sea levels are increasing more quickly than what models said would occur.

Deniers say:
Even if we stopped burning coal and oil today, the world would continue to warm. It’s too late to do anything about it. Why bother?

Science says:
Climate change is already happening today. How much the climate warms in the future is up to us.

We’re already feeling the effects of climate change. But that’s precisely why we need to both prepare for the climate change impacts we can’t avoid, and act quickly to curb the carbon pollution that’s causing the problem in the first place. It’s not an “either-or” decision — we need to do both. The longer we wait to make the transition to clean energy, the worse this problem will get for our children and future generations. It’s our choice.

Deniers say:
Weather forecasts are barely reliable a week out, so how can climate models tell us what will happen 100 years from today?

Science says:
We can't predict what the weather will be like on a given day in the year 2100 — but we are very confident the world will be a lot warmer.

Does a motorcycle accident down the street mean you can’t operate your electric car safely? No. In much the same way, “incorrect” weather forecasts don’t tell us much about the reliability of climate projections. Weather forecasters and climate scientists don’t look at the future the same way. A weather forecaster in New Jersey, for example, is interested in the chance of rain in Hoboken three days from now. On the other hand, a climate scientist is interested in whether the state of New Jersey will be wetter or drier on average 40 or 50 years from now. Much like a motorcycle and an electric car, weather and climate models include similar “parts," but they start with different kinds of data and are operated in different ways. Climate scientists can’t tell you with certainty how much the world will warm in 100 years. But they can say with certainty that the world will continue to warm. And the more carbon pollution we put in the atmosphere, the worse things will get.

Science says:
Arctic sea ice shrank to a record low in 2012, and second place was in 2007.

Full temperature data sets from the Arctic reveal it is warmer today than in 1940. The claim that the Arctic was warmer at earlier points in the 20th century is based on cherry-picked temperature data from a few stations. In fact, the Arctic summers of 2005, 2007, 2010, and 2011 were warmer than any time in at least the last 600 years.

Deniers say:
Arctic ice has melted before — it has nothing to do with climate change.

Science says:
It's not a coincidence. As carbon pollution warms the planet, Arctic ice is shrinking to record-lows.

Has Arctic sea ice changed before? Absolutely! Nobody disagrees with that. But arguing that man-made warming isn’t melting sea ice is like arguing humans can’t cause forest fires because they've been started by natural causes in the past. The amount of summer sea ice in the Arctic has dramatically declined over the last 30 years. And the oldest, thickest ice is getting thinner. Right now, Arctic sea ice is disappearing faster than at any time in at least the last few thousand years. If this pace keeps up, the Arctic could be ice-free in summer as early as 2035.

Science says:
Arctic sea ice shrank to a record low in 2012, and second place was in 2007.

The amount of sea ice in the Arctic cycles up and down from year to year. Despite these ups and downs, the amount of ice in the Arctic each summer has declined over the last half-century. Why? Because carbon pollution is warming the planet.

Science says:
Antarctica is doing better than the Arctic, but if global warming continues, none of the world's ice is safe.

Arctic sea ice is rapidly declining as the world warms. Since 1979, the extent of summer sea ice in the Arctic has declined by almost 1.2 million square miles. But Antarctic sea ice hasn't followed suit so far. In fact, there has been a slight gain in winter sea ice since 1979: about 0.2 million square miles. Why? Scientists aren't sure, but the ozone hole might be partly to blame. What we do know is that our planet is steadily warming due to pollution from dirty energy like oil and coal. At the current rate of warming, the Arctic could be nearly ice-free in the summer by 2035. And even in Antarctica, sea ice won't be around forever if the Earth keeps warming.

Deniers say:
The Earth’s climate has natural feedbacks that keep the planet cool. Otherwise, we’d be seeing runaway warming in the Arctic.

Science says:
The Arctic has been warming twice as fast as the rest of the world.

In recent decades, the Arctic has been warming at twice the global average rate. Recent research finds that melting sea ice plays a central role in this accelerated warming. How does this work? Sea ice acts like a bright white shield that reflects a portion of the sun’s rays back into space. Deep blue ocean water, however, is less effective in reflecting sunlight. It absorbs a lot more of the sun’s energy, which results in warming. Warming, of course, results in less ice, which in turn results in more warming. It’s a troubling feedback loop.

Science says:
There's a difference between sea ice and land ice. Antarctica's land ice, or glaciers, have been melting at an alarming rate.

To understand what’s going on with the ice in Antarctica, it’s important to know the difference between sea ice and land ice. Sea ice is frozen, floating seawater, while land ice (called glaciers or ice sheets) is ice that has accumulated over time on land. Overall, the Antarctic sea ice has been stable (so far) — but that doesn’t contradict the evidence that our climate is warming. Meanwhile, the ice sheet that covers most of Antarctica has lost more than half a trillion tons of ice in recent years. When land ice melts, meltwater flows into the ocean, contributing to sea level rise. Antarctica's melting land ice poses a direct threat to the hundreds of millions of people living on islands and near coasts.

Deniers say:
The Vikings lived in Greenland a thousand years ago when it was green, but died out when the climate got colder.

Science says:
Global warming is happening right now, and the more we pollute, the worse it will get. The Vikings have nothing to do with it.

Sure, parts of Greenland were probably greener during warmer periods of our planet’s history than they are now. But whether or not parts of Greenland were greener in the past is irrelevant to our present discussion of manmade climate change. The Earth's temperatures are increasing rapidly because of human activities. Temperatures vary around the globe, but most areas — including Greenland — are getting warmer. In fact, Greenland is losing more than 200 billion tons of ice every year. A rapidly warming climate isn't good news for Greenland or the rest of us.

Deniers say:
The thin ice on Greenland’s coast is melting. But so what? The thick ice at high altitudes is growing.

Science says:
Overall, Greenland is losing more than 200 billion tons of ice a year.

Scientists around the world report that Greenland is losing ice overall, despite small ice gains at high altitudes. And what’s more, the losses have drastically accelerated in recent decades. Right now, Greenland is losing more than 200 billion tons of ice a year! The meltwater from Greenland’s ice sheet continues to contribute to global sea level rise. A rapidly warming climate isn't good news for Greenland or the rest of us.

Science says:
Even when Greenland loses a small fraction of its ice, sea level goes up in a big way.

Greenland’s massive ice sheet contains enough ice to raise global sea level by about 20 feet. The total collapse of the Greenland ice sheet isn’t going to happen anytime soon, but ice loss from Greenland is accelerating. Research has shown that even a relatively small loss of ice from Greenland will result in significant sea level rise. And the more the ice sheet melts — we’re talking hundreds of billions of tons of ice a year — the more that rising seas endanger low-lying coastal communities around the world.

Deniers say:
Greenland’s massive ice sheet has survived worse periods of warming in the past, and there's no reason to expect catastrophe.

Science says:
Even when Greenland loses a small fraction of its ice, sea level goes up in a big way.

As our planet warms, ice melts in polar regions like Greenland. How long it will take for all of Greenland’s ice to disappear is hard to predict. A partial collapse is much more likely in this century. But that doesn’t mean the melting of Greenland’s massive ice sheet isn’t a huge problem. Research has shown that even a relatively small loss of ice from Greenland will result in significant sea level rise. And the more the ice sheet melts — we’re talking hundreds of billions of tons of ice a year — the more that rising seas endanger low-lying coastal communities around the world.

Deniers say:
We can't ignore the glaciers that are advancing and gaining ice.

Science says:
A few glaciers are advancing. Most are shrinking. Overall, they are losing 150 billion tons of ice a year.

Make no mistake: Globally, glaciers are shrinking, losing about 150 billion tons of ice a year. And while climate deniers may try to confuse the issue by “cherry picking” data or focusing on short-term variations, the long-term trend is crystal clear. Most of the glaciers worldwide are receding at an accelerating rate. Sure, there are isolated cases of glaciers that haven’t melted or are gaining ice. But as with any climate-related data, it’s important to stay focused on the big picture. If a conclusion isn’t based on large-scale, long-term trends, you’re not getting the whole story.

Deniers say:
The IPCC falsely claimed the glaciers in the Himalayas could be gone by 2035.

Science says:
Glaciers all over the world are losing ice — even in the Himalayas.

The United Nations Intergovernmental Panel on Climate Change (IPCC) is an international scientific body that reviews and assesses the most recent peer-reviewed climate change research produced worldwide. In its 2007 report, the IPCC warned that Himalayan glaciers could disappear by 2035 or sooner. The IPCC has since acknowledged that this statement came from a questionable source. And recent research shows the ice cover in the Himalayas may be shrinking more slowly than previously thought.

Here's the key, however: The Himalayas ARE losing ice. And this dispute over the Himalayas in no way changes the reality of what’s happening on a global scale. Glaciers all over the world are losing about 150 billion tons of ice a year, providing a natural indicator that the world is warming.

Deniers say:
Ice melting on Mount Kilimanjaro has local causes. So why should we believe in global climate change?

Science says:
It's not about one glacier or one mountain. Overall, glaciers are losing 150 billion tons of ice a year.

Mount Kilimanjaro is losing snow and ice. Is this because of global warming? Maybe, but changes in local weather patterns might be more important. Conditions have become drier, meaning less snow is falling to replenish the glaciers and reflect sunlight. Researchers have found that deforestation of the mountain’s foothills is a significant contributor to this drying trend. Still, as one researcher of Kilimanjaro’s deforestation put it: “The fact that the loss of ice on Mt. Kilimanjaro cannot be used as proof of global warming does not mean that the Earth is not warming. There is ample and conclusive evidence that Earth's average temperature has increased in the past 100 years, and the decline of mid- and high-latitude glaciers is a major piece of evidence."

The world has warmed about 1.5 degrees Fahrenheit since 1880 (that's 0.8 degrees Celsius). That may not sound like much, but we’re already starting to see what a warmer world has in store for us. Intense rainstorms, severe droughts and heat waves are becoming more frequent. Rising seas are damaging homes near the water. Some populations of animals are starting to die out. And that’s just 1.5 degrees! Now consider what could happen if we do nothing to limit the pollution that’s causing global warming. The best available estimates say the Earth will warm another 3 to 7 degrees Fahrenheit by 2100 (roughly 2 to 4 degrees Celsius). In other words, the more we pollute, the worse things will get.

Deniers say:
So what if there's a little climate change? What's wrong with a couple extra days at the beach?

Science says:
More extreme weather, rising seas, and escalating risks to our health. That's what we can expect as climate change gets worse.

Climate change isn’t just bad for polar bears. It’s bad for humans — for a lot of reasons. First, climate change increases the risk of extreme weather events like heat waves, droughts, and intense storms. Rising seas are already damaging homes and businesses near the water. But it doesn’t stop there. When it’s hot, the quality of the air we breathe gets worse, and that's a threat to our health. Ocean acidification, the result of oceans absorbing excess carbon pollution from the air, could destabilize fisheries and much of the oceanic food chain. It's widely believed that climate change will encourage the expansion of disease-bearing pests into new areas, like the ticks that carry Lyme disease. Wherever we live, climate change poses risks to both our economy and our way of life — and the time to start solving this problem is now.

Deniers say:
From world hunger to disease, the world has so many other problems that are more urgent than climate change.

Science says:
If you want your kids to grow up with the same opportunities you had, the time for solving climate change is now.

Climate change is an urgent threat to our economy, our health, and even our way of life. Carbon pollution stays in the atmosphere for hundreds of years. Even if we stopped emitting carbon pollution today, our world would continue to warm for a long time. Plus, man-made carbon pollution is setting “feedback loops” into motion that make the world warm even faster. For example, global warming is thawing frozen ground called “permafrost,” which then releases more heat-trapping gases into the air. We are already experiencing the impacts of warming — from deadly heat waves to a greater risk of extreme storms and drought. The longer we wait to address this problem, the more difficult and expensive it will get.

Deniers say:
The IPCC falsely claimed the Amazon is at risk of drought.

Science says:
Climate change puts the Amazon at risk of severe drought. The IPCC was correct.

The United Nations Intergovernmental Panel on Climate Change (IPCC) was actually right about Amazon rainforests. But here’s why you might be confused. An article in a British newspaper reported that the IPCC published false information about the Amazon rainforests in 2007. The information in question was a statement that 40% of the Amazon was susceptible to the effects of drought. This statement came from a report from the World Wildlife Fund instead of the original peer-reviewed studies. Neither the statement nor the number was wrong; the fault lies in the fact that the IPCC cited a "middleman” rather than the original, authoritative academic source. Since 2007, more studies have reinforced our knowledge of the Amazon’s susceptibility to drought. Oh, and the British newspaper retracted its original story.

Science says:
Plants need water, but is a flood a good way to water your crops? Too much carbon dioxide is bad news.

To grow, plants need three main things: sunlight, water and carbon dioxide. But that doesn’t mean we can jump to the conclusion that more carbon dioxide will be good for plants. More isn’t always better. A flood is not a good way to supply water to a forest. While experiments have shown that some plants respond well to higher carbon dioxide levels, others have shown that abnormally high levels of carbon dioxide can cause damage. Keep in mind that as carbon dioxide increases, temperatures also increase, rainfall patterns change, and some kinds of extreme weather events become more common and severe. This certainly spells bad news for plants. Don’t believe me? Ask the peanut farmers in drought-ridden Texas. Find out about the wine grapes in Australia and California, or the African cacao trees that are used to make chocolate. Climate change has not been kind to these plants so far.

Deniers say:
Plants and animals have adapted to adverse conditions in the past. They will adjust to climate change.

Science says:
For many species, including humans, the climate may be changing faster than we can keep up.

Climate change poses serious dangers for plant and animal life on Earth. Adaptation to changes in the environment can take a long time. That’s one big reason the rate of manmade climate change is so worrisome. For many species, our climate may be changing faster than they can keep up. And keep in mind that climate change isn’t the only way humans are altering the natural environment. Deforestation, urban sprawl and the use of toxic chemicals are environmental stress points making it ever more difficult for plants and animals to adapt. In short: At the rate we’re going, thousands of species could be in real danger.

Deniers say:
Despite the global warming you hear about, polar bears are making a comeback.

Science says:
Most polar bear communities are already declining. Melting ice is the greatest threat to their future.

Polar bears are found in 19 subpopulations around the Arctic. Of the 19 recognized polar bear subpopulations, scientists only have enough data to make accurate determinations about 12. Of those 12, eight are in decline, three are stable, and only one is increasing.
Animal populations decline for all sorts of reasons, and in the case of polar bears, being hunted by people is certainly one cause for concern. What’s also clear, however, is that the loss of sea ice is partly to blame for declines in at least four polar bear subpopulations. Sea ice is absolutely critical to the health of polar bears. They use it as a platform for hunting their prey, giving birth to their young, and traveling from one place to the next. Because of climate change, that platform of sea ice is melting, fast. And as climate change accelerates, polar bear habitat will be put in ever increasing danger.

Deniers say:
Corals have weathered worse, and they will adapt to the impacts of climate change.

Science says:
Climate change could make coral reefs lose their color and die.

The world’s oceans are getting warmer as we pump more and more carbon pollution into the atmosphere. Rising ocean temperatures are putting many of our coral reefs in severe danger, causing them to lose their color and die. That's called “bleaching.” Some species of corals are more tolerant than others to bleaching, but it’s a serious threat to most species. In 1998 alone, bleaching killed 16% of all coral on the planet! Corals would have an easier time dealing with mild bleaching events if they weren’t so threatened by other human activities, like overfishing. But experts agree the only way to keep corals and the species that depend on them healthy is to prevent bleaching in the first place. And that means reducing the carbon pollution that’s warming the oceans.

When humans send carbon pollution into the atmosphere, a lot of it stays there and warms the planet. But more than 25% of the carbon gets absorbed by our oceans. The more carbon pollution our oceans absorb, the more acidic they get. Since the start of the Industrial Revolution the ocean has become about 30% more acidic ⎯ with potentially serious consequences for marine life. Corals and shellfish have a harder time forming the hard shells they need to survive, and this threatens the habitats of fish and other sea creatures. This has serious implications for people, too, because we rely to a great extent on the bounty of the oceans to survive.

When we pollute the atmosphere with dirty energy like oil, coal, and gas, we end up with dirty weather. Around the world, devastating extreme weather events are becoming more common and severe. Take the United States, which during 2012 alone experienced the worst drought in decades, two of the most destructive wildfires in its history, and the unprecedented devastation from Superstorm Sandy. Of course, bad weather has always been with us, but climate change greatly increases our risk of extreme weather like heavy storms, droughts, and heat waves. We are playing games with our weather system with loaded dice. And the odds are not in our favor.

Deniers say:
Hurricanes are natural weather events and they have nothing to do with climate change.

Science says:
Get ready for more Category 5s. Even if hurricanes don't happen more often, they are likely to get more intense.

The science is settled when it comes to the cause of global climate change: It’s definitely happening and humans are responsible. But when it comes to the effect of climate change on tropical storms and hurricanes, the question isn’t fully settled yet. So what does the research show so far? It may well be that the FREQUENCY of tropical storms won't change much. But there is increasing evidence that storms will get MORE INTENSE as the climate warms — with higher wind speeds and more rainfall. There's a growing body of evidence that suggests hurricane intensity and climate change are linked. Stay tuned for more.

Sea level rise is measured both by tide gauges from around the world and by satellite. These independent data sets tell a consistent story: that global sea levels are rising, despite slight variations up and down each year. The evidence is clear that sea levels will continue to rise as the world gets warmer because of man-made pollution.

Science says:
Sea levels could rise more than a meter by the end of the century.

Globally, sea levels are rising due to the manmade pollution that's warming our climate. But how much will they rise in the future? Good question. Scientists know that the seas will continue to rise as the world warms, ocean water expands and glaciers and ice sheets melt. What they don’t know — yet — is how much the massive ice sheets in Greenland and Antarctica will melt by the end of the century. Because of that uncertainty, the United Nations Intergovernmental Panel on Climate Change (IPCC) — the international body that reviews and assesses the most recent peer-reviewed climate research from around the world — assumed in 2007 that the rate of ice loss from the poles wouldn’t change much over the next century. The emerging reality, however, is that the rate of melting is speeding up. This means the IPCC’s most recent projection of 18 to 59 centimeters by 2100 is in fact an underestimate, not an exaggeration. The latest scientific studies suggest that global sea levels could rise more than 1 meter by 2100.

Deniers say:
Many small islands are now higher above sea level than before.

Science says:
The more sea levels rise, the more difficult it gets for low-lying islands to keep their heads above water.

Globally, sea levels are rising as the world warms. But look at a finer scale, and you’ll see that sea level rise varies a lot from place to place. Areas like coastal Louisiana are sinking for both natural and manmade reasons, so they’re experiencing higher-than-average rates of sea level rise. In a few places, like Kodiak Island, Alaska, the land is rising — meaning that sea level is actually falling slightly. Coral reef islands (mostly found in the South Pacific) show a similarly complicated pattern. Some of these low-lying islands have survived the changes in sea level rise so far. But others have disappeared entirely. What’s clear is that as the rate of sea level rise increases, it will be more and more difficult for coral reef islands — and the people who live on them — to keep their heads above water.

Deniers say:
Some scientists believe in climate change, and some don't. It's a topic still up for debate.

Science says:
Climate change is real. Just ask 97% of the top climate scientists or any national science academy in the world.

There is overwhelming evidence that our climate is warming due to pollution from human activities. That's the conclusion reached by 97% of the top climate scientists and every major National Academy of Science in the world. When we burn dirty fossil fuels like oil and coal, and when we cut down forests that store carbon, we pollute our atmosphere and warm our planet. This is not controversial: It's a reality we've understood for decades.
Now here’s an experiment: Ask a good scientist what is known about a particular topic, and watch how quickly that scientist moves to what is unknown. Honesty about what is unknown is essential to sound science, and no entire field of science can ever be completely settled. But the basics of climate change ARE settled. In other words, there’s no dispute among the vast majority of climate scientists that our climate is warming, and that most of the recent warming is due to human activity.

Science says:
Climate change is real. Just ask 97% of the top climate scientists or any national science academy in the world.

Within the scientific community, there’s overwhelming consensus that man-made global warming is happening. According to a recent survey, 97 percent of top climate scientists (those with Ph.D.s who regularly publish the results of their research in peer-reviewed scientific journals) agree with that statement. And every major National Academy of Science in the world agrees that man-made climate change is happening and poses real threats. If 97 percent of doctors diagnosed you with a serious illness, would you ask the remaining 3 percent for their opinion before starting treatment? Of course not.

Science says:
Virtually all the peer-reviewed climate research shows that climate change is a reality.

In 2004, Professor Naomi Oreskes surveyed more than 900 peer-reviewed papers on global climate change published between 1993 and 2003. She found that zero papers rejected the consensus view that manmade climate change is occurring. 75% of the papers agreed with the consensus and 25% made no comment either way. Anthropologist Benny Peiser criticized the Oreskes survey and initially claimed he found 34 papers that rejected the consensus view. But a close inspection of those 34 papers found his criticism invalid. Peiser himself has said: “I do not think anyone is questioning that we are in a period of global warming. Neither do I doubt that the overwhelming majority of climatologists is agreed that the current warming period is mostly due to human impact.” Simply put, the facts support Oreskes.

Deniers say:
Only a few dozen so-called experts were behind the IPCC report.

Science says:
The IPCC publishes some of the world's most authoritative reports on climate change, which are checked, double-checked, and vetted by hundreds of scientists, and approved by governments around the world.

There is overwhelming scientific evidence that the world is warming; humans are responsible for most of the warming over the last 60 years; the world will continue to warm as we continue to pollute the atmosphere; and on balance, global warming will have very negative impacts. Those were the conclusions in 2007 from the United Nations Intergovernmental Panel on Climate Change (IPCC), an international body that summarizes the most recent climate science research from around the world. The evidence behind these reports is truly robust. Climate change is happening now and humans are to blame.

Deniers say:
Tens of thousands of scientists signed a petition agreeing that there's no evidence of catastrophic climate change.

Science says:
Who should you trust about climate change? Climate experts? Or veterinarians and electrical engineers?

97% of expert climate scientists agree that climate change is happening now and that humans are largely to blame. It turns out that very few of the 31,000+ people who signed the Oregon Institute of Science and Medicine’s petition are climate experts. The signatories include only 9,029 scientists with Ph.D.s and only 39 who were trained specifically in climatology. The list includes veterinarians and more than 2,000 electrical engineers. That’s a little like asking a plumber to assess repair plans for your leaky roof.

Deniers say:
More than half of all scientific papers either reject global warming or are neutral on the subject.

Science says:
This isn't controversial: It's reality. 97% of the top climate scientists agree that climate change is real.

Within the scientific community, there’s overwhelming consensus that man-made global warming is happening. According to a recent survey, 97% of top climate scientists (those with Ph.D.s who regularly publish the results of their research in peer-reviewed scientific journals) agree with that statement. And every major National Academy of Science in the world agrees that man-made climate change is happening and poses real threats. If 97% of doctors diagnosed you with a serious illness, would you ask the remaining 3% for their opinion before starting treatment? Of course not.

Deniers say:
After they gave up on the notion that global warming is real, they started calling it 'climate change' instead.

Science says:
You can call it global warming or climate change, but it's the biggest crisis humanity has ever faced.

“Global warming” and “climate change,” while closely related and sometimes used interchangeably, technically refer to two different things. “Global warming” applies to the long-term trend of rising average global temperature. “Climate change” is a broader term that reflects the fact that carbon pollution does more than warm our planet. It is also changing rain and snow patterns and increasing the risk of intense storms and droughts. The term “climate change” has actually been around longer than “global warming." Gilbert Plass published the study “The Carbon Dioxide Theory of Climatic Change” in 1956! And although “global warming” seems to have first appeared in a 1957 newspaper editorial, the term is widely attributed to Wallace Broecker’s 1975 paper “Climatic Change: Are We on the Brink of a Pronounced Global Warming?” Don’t fall prey to the idea that the increased popular usage of “climate change” means global warming is no longer happening. Both climate change and global warming are still a reality.

Deniers say:
The same scientists that raise the alarm about global warming were predicting an ice age more than 30 years ago.

Science says:
The climate crisis is happening now. An ice age may or may not happen in thousands of years.

The scientific evidence is clear: Climate change is happening now and human beings are to blame. In the 1960s and 70s, scientists knew that human activities were changing the Earth’s climate. But which factors would have a bigger effect? Global warming pollution, like carbon dioxide? Or pollution with a cooling effect, like the particles that make up haze? And would human activities override the natural factors that affect our planet’s climate? By the end of the 1970s, most scientists were coming to the conclusion that the world would indeed warm because of carbon pollution. This consensus grew even stronger over time: Today, 97% of climate scientists with Ph.D.s who are actively publishing in their field agree that humans are warming our climate.

Deniers say:
Galileo was also a skeptic — eventually he was shown to be more correct than the establishment trying to shout him down.

Science says:
Climate scientists use evidence and logic. Climate deniers use ideology and politics. So which one is more like Galileo?

Galileo used scientific evidence to prove the Earth revolved around the sun, and not the other way around, even though his idea went against the common thinking and religious ideology of his time. So who is more like Galileo: climate scientists, or people who deny the reality of climate change? Climate scientists are using the evidence-based rules of science to arrive at their conclusions. Deniers are using politics and ideology. Climate scientists are fighting against an age-old perception that humans can’t affect the climate. Deniers are trying to reinforce that out-of-date idea. Climate scientists are being dragged into court when their conclusions are unpopular or inconvenient. Deniers are doing the dragging. So who is more like Galileo? You be the judge.

Deniers say:
The East Anglia emails show that global warming is a fraud based upon falsified data and conspiracy.

Science says:
A few stolen emails taken out of context don't make climate change any less of a reality.

Here’s the thing. When something gets taken out of context, there’s an excellent chance it’ll be misinterpreted. And that’s exactly what happened with the emails that were stolen from the University of East Anglia in late 2009. After the emails were stolen and published online, a number of independent investigators examined the conduct of the scientists who wrote the emails. Ultimately, they concluded that nothing they said or did affected our understanding of climate science. There’s an overwhelming amount of evidence that man-made global warming is happening now. Focusing on a few emails that were taken out of context doesn’t make climate change any less of a reality.

Deniers say:
East Anglia scientists manipulated data in an effort to defend their global warming agenda.

Science says:
Several impartial reviews found the East Anglia scientists did nothing wrong.

In late 2009, private emails were stolen from climate scientists at the University of East Anglia's Climatic Research Unit (CRU). Deniers took select quotes from the emails out of context to claim that scientists fooled with temperature data. But they didn't. One independent review of the emails went back to primary data sources and was able to replicate CRU’s analysis of global temperature trends. Scientists who wrote the emails did withhold some data from their critics. They were wary about cooperating with people they didn’t trust. But that doesn’t lead to the conclusion that the data were tampered with. The data — and the scientific conduct of the scientists — held up under several independent reviews.

Deniers say:
Scientist Phil Jones came right out and said there has been no warming over the last 15 years.

Science says:
The ten hottest years on record have all occurred since 1998.

There is overwhelming evidence that humans are warming the climate by burning dirty energy like coal. Phil Jones, former director of the University of East Anglia’s Climatic Research Unit, has never claimed that global warming isn’t happening. It's true that some years are warmer than others, and 1998 was an unusually warm year (partly because of a particularly strong El Niño event). But overall, 2005 and 2010 were both hotter, and they tied for the hottest year on record. The ten hottest years on record have all occurred since 1998, and we can expect the world to get progressively warmer as long as humans pollute the atmosphere.

Science says:
Deniers took this email out of context. Kevin Trenberth has consistently said that manmade climate change is real.

If you read Dr. Kevin Trenberth’s peer-reviewed papers or listen to him give a presentation, you learn something about him pretty quickly. He is convinced that the planet is warming because of human activities. But he is also really, really bothered by how few satellites we have to collect important climate data. Dr. Trenberth meant as much when he sent a private email to other scientists about not being able to “account for the lack of warming.” That quote became famous when his email was stolen with more than 1,000 others during so-called Climategate in 2009. But the out-of-context quote from the email doesn’t accurately portray Trenberth’s views: that humans are warming the planet, but we don’t have all the tools we need to know exactly how much extra heat is being stored in the oceans.

Deniers say:
Secret emails from East Anglia prove that temperatures are going down, and scientists want to hide the decline from us.

Science says:
"Hide the decline" doesn't mean what you think it means. There is overwhelming scientific evidence of man-made global warming.

In late 2009, private emails were stolen from climate scientists at the University of East Anglia. Climate deniers pored over hundreds of pages of emails and seized on a few remarks they took out of context in a fruitless attempt to prove that climate change isn't real. One of these was scientist Phil Jones' use of the phrase "hide the decline." In context, the statement relates to Jones’ research on changes in global temperature. Although data from weather stations show that temperatures have risen since the second half of the 20th century, tree ring data in the northern latitudes show a decline. For this reason, it is widely acknowledged by scientists that tree-ring data are not reliable after 1960, and therefore should not be used for temperature reconstructions after that date. Jones no doubt chose his words poorly in referring to this fact. But several independent and thorough reviews of the stolen emails found Jones and other scientists did not have any scientific or ethical lapses.

Deniers say:
Scientists at East Anglia wanted to prevent their data from being made available to the public.

Science says:
Several impartial reviews found the East Anglia scientists did nothing wrong.

In late 2009, private emails were stolen from climate scientists at the University of East Anglia. Deniers pounced on a few remarks in the emails that appeared to suggest scientists had withheld documents the public had sought under a freedom of information request. So what really happened? It’s true that the scientists at times denied these requests for documents. However, an independent review of the stolen emails found that a flurry of requests were made in just a matter of days — a sign that the requests were made in an orchestrated attempt to overwhelm small research units with limited resources like East Anglia's Climatic Research Unit. Believing the requesters were not acting in good faith, researchers were wary about sharing their data with people they didn’t trust. The important thing is that their data held up. The facts remain the same. And those facts support the scientific conclusion that climate change is happening and human beings are to blame.

Deniers say:
East Anglia scientists blocked articles from publication if they conflicted with their worldview.

Science says:
Several impartial reviews found the East Anglia scientists did nothing wrong.

When a scientist submits a study to a journal, other experts review the study for quality, clarity and credibility. The peer review process and the high standards it helps maintain is part of what makes science unique. But when scientists’ stolen emails were published online in 2009, climate deniers took them out of context. Using a few select quotes from the emails, deniers accused some climate scientists of pressuring journals to reject papers that didn’t mesh with their worldviews. But these out-of-context quotes don't mesh with the facts. Multiple independent investigations have cleared the scientists of wrongdoing. One investigation in particular found the “rigour and honesty” of the scientists was “not in doubt.”

Science says:
The worst thing we can do for our economy is sit back and do nothing about climate change.

If we don't do anything about climate change, we will have serious economic problems on our hands. By one estimate, each ton of carbon pollution we put in the air costs society at least $85. Humans put about 35 billion tons of carbon pollution into the atmosphere every year! Here's the good news: A shift to a low-carbon economy could add $2.5 trillion to the world economy annually. That's why we need to stop changing the climate with carbon pollution from fossil fuels like oil and gas. Storms, droughts, sea level rise and the other impacts of climate change are terrible prospects for human beings and will put a heavy burden on the world economy.

Deniers say:
Life under the climate change agenda will be even worse for people living in poverty.

Science says:
Poor people are the ones who will suffer the most if we don't do something about climate change.

Contrary to what climate deniers would have you believe, it is the poor who will suffer the most if we don't do anything about climate change. Whether in the U.S. or elsewhere in the world, low-income people are often most vulnerable to extreme weather disasters linked to our warming climate. They’re the ones hurt the most when climate change reduces food and water supplies. They have the least access to the care they need when climate change threatens their health. Fortunately, clean energy is often a path out of poverty, as can already be seen in many parts of the world. For example, in Bangladesh today, over one million homes have solar panels. In many cases, a single solar power system is enough to keep a family fed, keep their businesses open longer, and help their children study after the sun goes down. Fighting climate change by reducing carbon pollution is a win-win for all of us.

Deniers say:
Switching to renewable energy would be dangerous to the economy.

Science says:
Clean energy is one of the world's fastest growing industries, and it employs millions of people in America alone.

The best way to create jobs and grow the economy is to invest in clean, renewable energy like wind, solar and geothermal power. Clean energy is one of the world's fastest growing industries. Global investment in clean energy climbed to $260 billion worldwide in 2011, a record high. That’s a 5% climb compared to 2009 and five times the investment made in 2004. And 2010 was the first time that investment in renewable energy surpassed investment in fossil fuels. According to one estimate, global clean energy investment will grow by another $140 billion by 2021.

All this investment creates jobs. Just look at the solar industry in the U.S., where jobs more than doubled from 2009 to 2011. According to one comprehensive study, the green energy economy (which includes clean energy) employs 3.1 million Americans today. Clean energy investment is a smart jobs plan. Pollution isn’t.

Deniers say:
The wind stops blowing, the sun is covered by clouds, and the only backup for that unreliability is good old oil and coal.

Science says:
All day and all night, rain or shine, renewable energy is a reliable way to keep the lights on in the 21st century.

Clean, renewable energy is turning out to be just as reliable as dirty fossil fuels — with the added benefit that it doesn't pollute the air or warm our climate. The right combination of a more flexible power grid and appropriate sources of clean energy can provide around-the-clock power — even when the sun isn’t shining or the wind isn’t blowing. In fact, by adding more clean energy, we’re making the entire grid more dependable. Which is a good thing, because every power plant is vulnerable to disruption. Take the coal-fired power plants in Nebraska, for instance, that were temporarily shut down in 2011 by flooding. One way engineers and scientists are working to improve the reliability of clean energy is through battery storage, which saves electricity when demand is low (or production is high) and releases it when demand is high (or production is low).

Clean energy technology will also get better as consumer demand increases. That trend is already underway: Clean energy is one of the fastest-growing industries in the world, accounting for more than half of all new electric power added in 2009 and 2010.

Deniers say:
Renewable energy is a nice idea, but it just isn’t economically viable.

Science says:
The wind and the sun are free, and they also don't ruin the climate.

The claim that renewable energy is too expensive is out-of-date propaganda. The price of clean, renewable energy is plummeting. In some parts of the U.S., it's now almost as cheap to buy solar as it is to buy electricity from coal or gas. New estimates suggest wind power now costs customers about the same as natural gas in some areas and is even a little cheaper than coal. So it's no surprise that clean energy is one of the world's fastest growing industries, and already makes up 20% of the world's energy supply. Best of all? When you use clean energy, you don't have to pay for the millions of kids with asthma as a result of air pollution from coal. You don't have to pay Middle Eastern dictators to hand over their oil supplies. And you don't have to pay for the devastating financial and human impacts of climate change.

Deniers say:
Shifting over to clean energy would require changing our way of life and shutting down our economy, and wouldn’t even solve the problem.

Science says:
Is it too hard to go to the moon, eradicate smallpox or end apartheid? Is it too hard to build a computer that fits in your pocket? No? Then it's not too hard to build a clean energy future, either.

When was the last time we used “it’s too hard” as an excuse? Is that what they said in the U.S. when President Kennedy wanted to go to the moon? Is that what they said before the Iron Curtain fell in Eastern Europe? Or before smallpox was eradicated from the face of the earth? No. In just the same way, we’re already seeing that shifting to clean energy is a whole lot easier than we thought. Clean energy accounted for more than half of all new electric power added in 2009 and 2010. In 2009, China boosted its clean energy generation to 226 Megawatts four times the annual electricity use of the United Kingdom. Global investment in clean energy climbed to record highs in 2011, topping out at $260 billion worldwide. That’s a 5 percent climb compared to 2009 and five times the investment made in 2004. The transition to clean energy won’t happen overnight, but it will happen sooner than we think.

Deniers say:
Tar sands oil that will be carried by the Keystone XL pipeline is no worse than any other oil.

Science says:
Barrel for barrel, tar sands oil is even worse for the climate than conventional oil.

Oil is a dirty fossil fuel, and it’s one of the leading causes of the carbon pollution that’s warming our planet. But some forms of oil are even worse than others. Overwhelmingly, experts agree that oil mined from tar sands in Alberta, Canada is far worse for the climate than most of the oil currently produced and sold in the United States, because of the added pollution from extracting, refining, and delivering it. Here’s why: Tar sands oil requires more effort to extract and transport; it needs more chemical processing to meet U.S. fuel standards; and open-pit mining is extremely destructive to soils and forests that naturally remove carbon from the air. Our urgent priority should be to stop using dirty energy like oil, and move toward clean, renewable energy sources. But we should especially avoid using more tar sands oil that would be transported through projects like the Keystone XL pipeline.

Science says:
Natural gas is a bridge to nowhere. It undermines progress on clean energy and is dangerous for our climate.

Natural gas is a dirty fossil fuel. Like coal and oil, it produces carbon pollution that disrupts our climate and greatly increases our risk of costly disasters. Nonetheless, natural gas is often touted as a temporary “bridge fuel” that will help us move away from coal and toward renewable energy like wind and solar. But here’s the thing: We don’t have to wait. The longer we delay our transition to truly clean energy, the worse off we’ll be. Natural gas is mostly made of methane, which is a greenhouse gas over 20 times more powerful than carbon dioxide. If methane leaks from natural gas extraction and distribution prove to be as high as initial studies indicate, natural gas could even be worse for our climate than coal. Moreover, the International Energy Agency found that a large natural gas boom, even with practices to reduce methane leakage, would still put us on track for an unsustainable global temperature rise of 3.5 degrees Celsius. The good news? We have viable alternatives. In 2012, the top new electricity source in the U.S. was wind power — not natural gas. To reduce carbon pollution, we need to ramp up our clean energy use without any further delay — and not get sidetracked by dirty energy like natural gas.

Science says:
Don’t be fooled by the promise of “clean” coal. “Clean coal” is the industry’s tooth fairy. There’s no such thing.
Wind and solar on the other hand, are real clean energy technologies that are viable today.

In reality, there’s no such thing as "clean coal” — it’s a false solution.
Coal is a dirty fuel — from start to finish. During the coal mining process mountaintops are blasted away and toxic slurry ponds left behind. Burning coal results in pollutants that are harmful to human health, like mercury and smog. As if this weren't enough, worldwide, more carbon pollution comes from the burning of coal than any other fuel. A limited number of coal plant operators are now experimenting with capturing the carbon pollution their plants produce and storing it underground. But the present cost of this technology — known as Carbon Capture & Storage (CCS) — is extremely high and safe storage areas are limited. While CCS may play a limited role in a low-carbon future, it shouldn’t be mistaken for a quick fix to the climate crisis. To make meaningful progress in curbing climate change we need to invest in real clean energy sources, like wind and solar, which are more economically viable and better for our climate and health, too. That’s the bit Big Coal won’t advertise.

Deniers say:
The Climate Action Plan will kill jobs and hurt the economy.

Science says:
The Climate Action Plan will save lives by reducing carbon pollution while creating good jobs and providing billions of dollars in annual savings to the U.S. It’s a win-win-win scenario.

Implementing the President’s Climate Action Plan will reduce pollution and provide significant economic benefits to the U.S.
From 2011 to 2012, the U.S. experienced 25 weather and climate disasters with damages totaling over $1 billion each, affecting the lives and livelihoods of many working families. Many such events are expected to become more frequent and intense with climate change. President Obama recognizes the social and economic threat that climate change poses, and his Climate Action Plan (CAP) is a vital step toward addressing it, transitioning the U.S. to a cleaner, more sustainable economy and away from the dirty fossil fuels that pollute our air and are the biggest contributors to climate change. His plan targets four areas where the U.S. can achieve significant reductions in emissions: new and existing power plants, energy efficiency, hydrofluorocarbons, and methane. Targeting these four areas will reduce dangerous carbon pollution and help curb climate change. And, the best part of this plan is that it will provide tremendous economic benefits. For example, a dollar invested in clean energy creates three times as many jobs as would be created by the fossil fuel industry, and workers in the clean economy earn better wages than the median American wage. This plan will create good jobs, save lives, and provide billions of dollars in annual savings to the U.S.

Deniers say:
The planet isn’t warming, and even the IPCC now admits it.

Science says:
Global warming hasn’t stopped. It’s just slowing down over a speed bump, before it likely picks up speed again.

Many indicators tell us the earth is still warming, and surface air temperature is just one of them.

Surface air temperatures don’t rise or fall at constant rates. When you plot them on a graph, the rising line doesn’t look like a railing (straight), but more like the stairs themselves (with intermittent landings where things flatten out between steps and then go up again).

The second important thing to remember is that real scientists don’t look at short periods of time to evaluate what is and isn’t happening to the planet. Why? Because when you arbitrarily pick start and end dates within 10 or even 20 years, there’s just not enough data to give an accurate picture and it’s easy to skew the results. That’s why scientists prefer to rely on sustained, long-term trends over several decades.

It’s a fact that the first decade of the 21st century was the hottest decade on record. At the same time, the IPCC’s Fifth Assessment Report does note that between 1998—2012, temperatures rose at a slightly slower rate than the longer-term rate seen since the mid-20th century.

Why? Scientists suggest it could be because oceans have absorbed a lot of the heat that would otherwise have stayed in the atmosphere.

But can the oceans retain this absorbed heat forever? No.

Other possible reasons for the slower rate of surface warming include temporary cooling influences like a solar minimum (a low point in the sun’s activity), and the effect of natural and man-made aerosols, which block some of the sun’s radiation from reaching the earth. With such cooling influences, the fact that we have NOT cooled in the last decade is actually a strong sign that global warming continues unabated.